docs: def select_distinct_column(engine, *columns):
      """
      Select distinct column(columns).
  
      :returns: if single column, return list, if multiple column, return matrix.
  
      **中文文档**
  
      distinct语句的语法糖函数。
      """
      if isinstance(columns[0], Column):
          pass
      elif isinstance(columns[0], (list, tuple)):  # pragma: no cover
          columns = columns[0]
      s = select(columns).distinct()
      if len(columns) == 1:
          return [row[0] for row in engine.execute(s)]
      else:
          return [tuple(row) for row in engine.execute(s)]